System for handling fragmented ice

ABSTRACT

A system for depositing fragmented ice in vertical wire mesh cylindrical baskets. A pneumatic system moves the ice in a stream of air to the basket being filled through a flexible hose which has at its free end a precipitator unit or ice-air separator with a discharge opening at its bottom end. To fill a basket, the precipitator unit is moved down through the top of the basket with the discharge opening at the bottom. The ice is separated from the air in the precipitator unit, and the air is discharged upwardly and a body of ice accumulates and closes the discharge opening. The precipitator unit is moved upwardly in the basket at a rate depending upon the rate of delivery and accumulation of ice. During that upward movement the bottom lip around the discharge opening is always below the level of the accumulated ice so that the ice at the opening and beneath it is quiescent. Positioned adjacent the basket wall around the discharge opening is an annular heater which melts a small amount of the ice at the lip. The subcooled condition of the adjacent ice produces recongealing or refreezing so as to sinter together the ice fragments which are in contact with the basket wall. That produces a composite shell formed by the sintered shell of ice adhered to the basket wall. The immediate effect of the shell is to assist in preventing the loss of ice particles through the basket wall, even though the shell may not be a solid layer of ice. The shell also increases the resistance to the discharge of air through the discharge opening of the precipitator unit so that the air is forced upwardly and it flows at a slow rate and does not carry ice particles with it. The cylindrical shell also tends to reduce sublimitation of the ice so as to preserve the enclosed ice. The system is particularly useful in providing &#39;&#39;&#39;&#39;permanent &#39;&#39;&#39;&#39; bodies of borated ice in an atomic energy power plant for the absorption of radiation and heat in the event of an explosion.

United States Patent 1 Field Nov. 26, 1974 SYSTEM FOR HANDLING FRAGMENTED ICE [76] Inventor: Crosby Field, 8029 Harbor View Ter., Brooklyn, NY. 11209 [22] Filed: June 20, 1972 [21] Appl. N0.: 264,613

[52] US. Cl 62/67, 62/137, 176/37 [51] Int. Cl G21c 3/00, G2lc 9/00 [58] Field of Search 62/67, 75, 137; 176/37 [56] References Cited UNITED STATES PATENTS 3,580,806 5/1971 Weems et a1. 176/37 Primary ExaminerWilliam E. Wayner Attorney, Agent, or Firm-Curtis, Mom's & Safford [57] ABSTRACT A system for depositing fragmented ice in vertical wire mesh cylindrical baskets. A pneumatic system moves the ice in a stream of air to the basket being filled through a flexible hose which has at its free end a precipitator unit or ice-air separator with a discharge opening at its bottom end. To fill a basket, the precipitator unit is moved down through the top of the basket with the discharge opening at the bottom. The ice is separated from the air in the precipitator unit, and the air is discharged upwardly and a body of ice accumulates and closes the discharge opening. The precipitator unit is moved upwardly in the basket at a rate depending upon the rate of delivery and accumulation of ice. During that upward movement the bottom lip around the discharge opening is always below the level of the accumulated ice so that the ice at the opening and beneath it is quiescent.

Positioned adjacent the basket wall around the discharge opening is an annular heater which melts a small amount of the ice at the lip. The subcooled condition of the adjacent ice produces recongealing or refreezing so as to sinter together the ice fragments which are in contact with the basket wall. That produces a composite shell formed by the sintered shell of ice adhered to the basket wall. The immediate effect of the shell is to assist in preventing the loss of ice particles through the basket wall, even though the shell may not be a solid layer of ice. The shell also increases the resistance to the discharge of air through the discharge opening of the precipitator unit so that the air is forced upwardly and it flows at a slow rate and does not carry ice particles with it. The cylindrical shell also tends to reduce sublimitation of the ice so as to preserve the enclosed ice. The system is particularly useful in providing permanent bodies of borated ice in an atomic energy power plant for the absorption of radiation and heat in the event of an explosion.

10 Claims, 2 Drawing Figures SYSTEM FOR HANDLING F RAGMENTED ICE This invention relates to handling ice, and particularly providing bodies of ice in baskets or the like from fragmented ice, for example, borated ice as a safety shield in an atomic energy power plant.

An object of this invention is to provide improved methods and systems for delivering fragmented ice and depositing it in an efficient and dependable manner. Another object is to provide a system and method for forming bodies of ice in nuclear power plants to absorb heat and radiation in the event of an explosion. A further object is to provide for the above with apparatus which is simple, efficient and dependable in use. These and other objects will be in part obvious and in part pointed out below.

IN THE DRAWINGS:

FIG. I is a vertical sectional view of the precipitator unit within an ice storage basket in a system constituting one embodiment of the invention; and,

FIG. 2 is a somewhat schematic representation of the system of which the precipitator unit of FIG. 1 is a part.

Referring to FIG. 1 of the drawing, a cylindrical wire mesh basket 2 has its lower portion filled with a body 4 of subcooled fragmented ice which contains 0.02 percent of boron and is of the type known as borated ice. Positioned within the basket at the top of the body of ice is a precipitator unit 6 which has a sheet metal casing 8 which is substantially cylindrical but which is slightly tapered so as to have a greater diameter at the bottom than at the top. Concentrically positioned in casing 8 is an air-product supply tube 10 which is connected at its top to supply hose 12 (see also FIG. 2) and which terminates at the bottom in a flared discharge unit 14. Casing 8 has a rectangular transparent window 16 which extends from below the normal level of ice in the bottom of the casing to substantially the center of the discharge unit 14. A pair of control thermistors l8 and 20 is supported on a rod 22, respectively, slightly above the bottom of unit 14 and slightly below the surface of the body of ice. These thermistors are connected through electrical wires in rod 22 to the control system to be discussed below.

During operation, a stream of air which is loaded with fragmented ice flows through hose 20 to tube 10 and is discharged through unit 14. The fragments ofice fall from the stream of air and the air reverses direction and flows upwardly through the annular passageway 23 between the peripheral edge 24 of unit 14 and the adjacent surface of casing 8. The annular passageway 23 provides a restriction or bottleneck" to the air flowing upwardly, and above edge 24 the passageway increases in cross-section. The outward flare of unit 14 permits the incoming air to move radially outwardly toward edge 24, while the ice particles including the fines continue downwardly aided by the action of gravity and momentum. The body of ice in the bottom of casing 8 and in the basket below acts to prevent the escape of air downwardly.

Above unit 14, the cross-sectional area of the annular passageway 25 between tube 10 and casing 8 is substantially greater than the cross-sectional area of tube 10. Hence, the air moves upwardly at a relatively slow rate compared with the rate of downward flow through the tube. The tops of casing 8 and tube 10 are connected by a wire mesh annular wall 26 which supports the casing, and the air escapes through wall 26 without substantial restriction. The slow rate of the upward flow of air is not sufficient to entrain and move ice particles upwardly so that there is no loss of ice.

At the stage of the filling of basket 2 which is represented in FIG. 2, the precipitator unit is being moved upwardly at substantially the rate that the level of ice is rising in the column as it is delivered and accumulated at the level 28 in the bottom of the precipitator unit. The control system acts in response to the temperatures of the thermistors l8 and 20 to maintain thermistor 20 at the reduced temperature of the ice and to maintain thermistor 18 at the higher temperature of the air which is being discharged.

If there is a reduction in the rate of delivery of ice so that the upward movement of precipitator unit 6 raises thermistor 20 above the level of the ice, that thermistor will be subjected to the air temperature which is above the ice temperature. The control system acts in response to that increase in the temperature of thermistor 20 to decrease the rate at which precipitator unit 6 is being moved upwardly. Therefore, the level of ice will raise more rapidly than the thermistors move upwardly and thermistor 20 will again be covered by the ice. If the ice builds up above the bottom of unit 14 there will be sufficient ice in contact with thermistor 18 to reduce its temperature below the normal temperature of the air. That decrease in the temperature of thermistor 18 causes the control system to increase the rate at which precipitator unit 6 is being moved upwardly, with the result that the precipitator unit is drawn upwardly to the proper level with respect to the top surface 28 of the ice. Hence, the thermistors act as limit stops for the level of the ice with respect to the precipitator unit.

Mounted at the bottom of casing 8 on its outer wall is an electrical resistance heater unit 30 which is connected to the control system through wires in rod 22. Resistance heater unit 30 produces a carefully controlled amount of heat which melts a small portion of the ice at the bottom edge of casing 8. The water thus produced seeps down onto the fragmented ice at the bottom edge of the casing, and is recongealed or refrozen by the subcooled condition of the fragmented ice and it forms an ice shell 32 at and somewhat enclosing the wires of the wire mesh basket. Ice shell 32 and the wall of the wire mesh basket form an enclosure for the fragmented ice. Initially, shell 32 may tend to have openings in it, but after an extended period of time there is a tendency for the shell to build up into a rather thick imperforate crust. However, even initially, shell 32 provides a substantial restriction to the escape of air which might otherwise pass directly through the body of ice, and the shell prevents the sifting of ice particles from the basket.

It is thus seen that precipitator unit 6 provides a dependable and efficient means for separating the ice from the air and for discharging the air free of ice. Also, the precipitator acts in combination with the basket wall to provide a reinforced enclosure shell for the body of fragmented ice. The fragmented ice contains pieces of varying size so as to provide a relatively dense body of ice in the basket.

FIG. 2 illustrates the entire ice delivery system which includes precipitator unit 6, shown on a reduced scale. Hose 12 delivers the air-ice stream to precipitator unit 6, and it also supports the precipitator unit. The free end of hose 12 extends vertically downwardly from a pulley 40 which is mounted to rotate freely in a pair of bearings 42 and supported by a portable frame 44, which is anchored in a fixed position at the level shown above the top of the basket 2 which is being filled with ice. Hose 12 extends from pulley 40 around a moveable pulley 46 and thence has its end anchored to a unit 48 through which compressed air and fragmented ice are delivered, and in which the ice is entrained into the stream of air. Hose 12 is reinforced to provide a desired strength and to prevent it from collapsing on the pulley.

Pulley 46 is mounted to rotate freely upon a shaft 50 which also has a pair of flanged wheels 52 upon its opposite ends. Each of the wheels 52 rides upon a rail 54 so that pulley 46 can be moved horizontally to and from pulley 40. Hose 12 is held taut between its anchor to unit 48 and precipitator unit 6, and the movement of pulley 46 toward pulley 40 produces slack in hose 12 and the weight to precipitator unit 6 is sufficient to draw the nose around pulley 40, and the precipitator unit is thereby lowered into the basket. The movement of pulley 46 to the left away from pulley 40 draws hose l2 upwardly around pulley 40 and elevates the precipitator unit as referred to above.

The positioning and movement of pulley 46 is controlled by a reel unit 56 which has a reel 58 driven by a motor 59 and upon which a cable 60 is wound. The free end of cable 60 is connected to a clevis 62 which has its two arms journaled respectively upon the ends of shaft 50, and the clevis extends free of pulley 46 and cable 60 extends in general alignment with the center of the pulley. Hence, when reel 58 is fixed, cable 60 holds pulley 46 in a fixed position and the hose and the cable are held taut by the weight of the precipitator unit. However, the unwinding of cable 60 from the reel permits pulley 46 to move toward pulley 40 and the precipitator unit draws the hose downwardly and moves into the basket. Counterwise, the winding of cable upon reel 58 moves pulley 46 to the left and elevated the precipitator unit as discussed above.

, Motor 59 is a precisely operating reversable motor which is connected through wires 72 to a controller 64. Controller 64 has a self-winding reel 66 upon which a set of control wires 68 are wound. Wires 68 extend around a pulley 70 and then downwardly to precipitator unit 6 where they extend through rod 22, to thermistors l8 and 20 and resistance unit 30. Control unit 64 operates motor 59 to first lower the precipitator unit into the basket to be filled. When the delivery of ice is started, control unit 64 operates motor 59 to elevate the precipitator unit as explained above. When basket 2 has been filled, the portable frame 44 with all of the components attached to it is moved to a new location so that the precipitator unit is positioned directly over another basket and the basket filling procedure is repeated. The invention contemplates that the body of ice in each basket will be replaced from time to time.

When basket 2 is completely filled, the basket and ice form a relatively stable composite article with an enclosure which comprises the cylindrical shell formed by the basket wall and the layer of ice attached thereto. That shell encloses the fragmented ice and protects it, e.g., from deterioration which would result from the free circulation of air through the ice. The invention contemplates that other means may be provided to support and move the precipitator unit within the basket.

An important aspect of the invention is the proper control of the movement of the precipitator unit upwardly during the basket filling operation. The simple control by the thermistors acting as temperature sensing elements can work very satisfactorily. However, under some circumstances the rate of ice delivery may be controlled with sufficient accuracy to make it possible to omit that precise control, and then, for example, rely upon visual observation through window 16 to insure that the proper ice level is maintained within the precipitator unit. While only one embodiment is shown in the drawings, it is understood that modifications and alternative constructions are contemplated within the scope of the claims.

What is claimed is:

l. The method of depositing a column of fragmented ice which comprises the steps of, entraining ice fragments in air to form a composite ice-air stream, passing said ice-air stream in a downward direction to the bottom of the zone where the column is to be formed, performing primary ice separation by stopping the downward movement of the air and the continued movement of the ice fragments by the combined action of gravity and momentum, discharging the air upwardly through a closed passageway having a cross-sectional area such that the rate of air flow is less than that at which the ice particles will be entrained, and utilizing the accumulated ice to reduce the tendency for air to be discharged downwardly.

2. The method as described in claim 1 wherein the cross-sectional area of the air-ice stream is increased adjacent the zone of separation whereby the rate of air flow is reduced.

3. The method as described in claim 2, which includes, providing a restriction to the flow of air at the outlet of the zone of separation.

4. The method as described in claim 1 which includes, the steps of, melting ice particles at the periphrey of the zone where ice particles have been accumulated and refreezing the water thus formed and providing a substantially continuous layer of ice around the vertical surface of the column as it is formed.

5. The method as described in claim 4 which includes the step of subcooling said ice fragments so that said refreezing of water is performed by the absorption of heat by the ice fragments.

6. An ice-separating apparatus for separating fragmented ice from a stream of air in which it is entrained, a shell construction having an ice discharge opening and an adjacent chamber in-which the fragmented ice can accumulate, means for forming an inlet passageway for an air-ice stream and terminating adjacent said chamber whereby the momentum of the moving ice particles carries them into said chamber, means forming an air discharge passageway in counter-current relationship to the air-icestream and having a crosssectional area which is substantially greater than the cross-sectional area of the air-ice stream whereby the air escapes at a speed which is insufficient to entrain the ice particles.

7. In combination with the apparatus as described in claim 5, a vertical basket formed by a perforated wall and of slightly greater horizontal dimensions than said shell construction, and whereby said chamber is positioned at the bottom of said shell construction and the accumulated ice moves from said chamber into said basket as said shell construction is moved upwardly in the basket whereby a body of accumulated ice in said chamber closes the bottom of said shell.

8. In combination with the ice-separating apparatus as described in claim 5, moving means to move said iceseparating apparatus downwardly into and thence upwardly from an ice receiving receptacle having a perforate vertical wall, and means to control said upward movement in accordance with the level of the ice accumulated in said chamber.

9. The apparatus described in claim 6 wherein said means to control includes two temperature sensing elements, one of which is positioned below the normal level of the accumulated ice in said chamber and the other of which is positioned at or above the normal upper level of the accumulated ice and acting to decrease said rate of upward movement when said first named element senses an elevation in temperature to that of the general level of the air and to increase said rate when the temperature of said second mentioned element is reduced to the general level of the ice.

10. A system comprising the apparatus described in claim 7 which includes means to entrain fragmented ice into a stream of air to form an air-ice stream and to deliver said air-ice stream to said air-ice separating apparatus. 

1. The method of depositing a column of fragmented ice which comprises the steps of, entraining ice fragments in air to form a composite ice-air stream, passing said ice-air stream in a downward direction to the bottom of the zone where the column is to be formed, performing primary ice separation by stopping the downward movement of the air and the continued movement of the ice fragments by the combined action of gravity and momentum, discharging the air upwardly through a closed passageway having a cross-sectional area such that the rate of air flow is less than that at which the ice particles will be entrained, and utilizing the accumulated ice to reduce the tendency for air to be discharged downwardly.
 2. The method as described in claim 1 wherein the cross-sectional area of the air-ice stream is increased adjacent the zone of separation whereby the rate of air flow is reduced.
 3. The method as described in claim 2, which includes, providing a restriction to the flow of air at the outlet of the zone of separation.
 4. The method as described in claim 1 which includes, the steps of, melting ice particles at the periphrey of the zone where ice particles have been accumulated and refreezing the water thus formed and providing a substantially continuous layer of ice around the vertical surface of the column as it is formed.
 5. The method as described in claim 4 which includes the step of subcooling said ice fragments so that said refreezing of water is performed by the absorption of heat by the ice fragments.
 6. An ice-separating apparatus for separating fragmented ice from a stream of air in which it is entrained, a shell construction having an ice discharge opening and an adjacent chamber in which the fragmented ice can accumulate, means for forming an inlet passageway for an air-ice stream and terminating adjacent said chamber whereby the momentum of the moving ice particles carries them into said chamber, means forming an air discharge passageway in counter-current relationship to the air-ice stream and having a cross-sectional area which is substantially greater than the cross-sectional area of the air-ice stream whereby the air escapes at a speed which is insufficient to entrain the ice particles.
 7. In combination with the apparatus as described in claim 5, a vertical basket formed by a perforated wall and of slightly greater horizontal dimensions than said shell constrUction, and whereby said chamber is positioned at the bottom of said shell construction and the accumulated ice moves from said chamber into said basket as said shell construction is moved upwardly in the basket whereby a body of accumulated ice in said chamber closes the bottom of said shell.
 8. In combination with the ice-separating apparatus as described in claim 5, moving means to move said ice-separating apparatus downwardly into and thence upwardly from an ice receiving receptacle having a perforate vertical wall, and means to control said upward movement in accordance with the level of the ice accumulated in said chamber.
 9. The apparatus described in claim 6 wherein said means to control includes two temperature sensing elements, one of which is positioned below the normal level of the accumulated ice in said chamber and the other of which is positioned at or above the normal upper level of the accumulated ice and acting to decrease said rate of upward movement when said first named element senses an elevation in temperature to that of the general level of the air and to increase said rate when the temperature of said second mentioned element is reduced to the general level of the ice.
 10. A system comprising the apparatus described in claim 7 which includes means to entrain fragmented ice into a stream of air to form an air-ice stream and to deliver said air-ice stream to said air-ice separating apparatus. 